The present invention relates to a device for inflating and deflating vehicle tires whether the vehicle is moving or standing still. Some devices of this general character have been designed; however, most of them require that the device be integrated into the original vehicle design. They do not contemplate being easily retrofitted into existing vehicles. The present invention contemplates structural modifications on an existing vehicle to give the existing vehicle the capability of inflating and deflating the tires while the vehicle is at rest or moving.
Having the capability to increase or decrease the tire pressure while the vehicle is moving is desirable because it allows the driver to increase or decrease the amount of surface traction the tires have as the terrain or conditions warrant. When a vehicle is traveling over hard terrain it is desirable to have a relatively low tire surface area to reduce wear on the tire and decrease the vehicle tire rolling resistance. However, when the vehicle is traveling on soft terrain greater traction is needed. The traction of the tire is increased by reducing its air pressure. As the tire is deflated, the surface area in contact with the ground increases, as does the traction of the vehicle.
A tire inflation-deflation system is also useful when the terrain or conditions remain constant but the payload weight changes. When the vehicle payload is increased, more force is exerted on the tire. To keep the traction mated to the terrain the tire pressure must be increased; conversely, as the payload is reduced the tire should be deflated if the traction is to remain at an optimum.
The following U.S. Patents are believed to be representative of air inflation-deflation systems heretofore used and/or proposed for use on vehicles:
Burggraf 1,112,596 PA1 Mitchell 1,657,023 PA1 Holbrook 2,989,999 PA1 VanWinsen 3,102,573 PA1 Goodell 4,431,043 PA1 Swanson 4,434,833
The prior art patented disclosure most pertinent to my invention is believed to be the disclosure embodied in U.S. Pat. No. 4,431,043. My invention is believed to represent an advance over that patent disclosure in that my system is more easily and more economically added to existing vehicles. Additionally, my add-on system is believed to have advantages as regards easier (less costly) maintenance of certain slip ring air seals required in such systems.
My invention is directed particularly to an add-on passage system installable on the rear axle assembly of an existing military vehicle to provide the vehicle with central tire pressure inflation-deflation capability. The principle object of the invention is to provide an add-on air passage system that can be economically installed and maintained.